3,283 research outputs found

    Machine learning with the hierarchyā€ofā€hypotheses (HoH) approach discovers novel pattern in studies on biological invasions

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    Research synthesis on simple yet general hypotheses and ideas is challenging in scientific disciplines studying highly contextā€dependent systems such as medical, social, and biological sciences. This study shows that machine learning, equationā€free statistical modeling of artificial intelligence, is a promising synthesis tool for discovering novel patterns and the source of controversy in a general hypothesis. We apply a decision tree algorithm, assuming that evidence from various contexts can be adequately integrated in a hierarchically nested structure. As a case study, we analyzed 163 articles that studied a prominent hypothesis in invasion biology, the enemy release hypothesis. We explored if any of the nine attributes that classify each study can differentiate conclusions as classification problem. Results corroborated that machine learning can be useful for research synthesis, as the algorithm could detect patterns that had been already focused in previous narrative reviews. Compared with the previous synthesis study that assessed the same evidence collection based on experts' judgement, the algorithm has newly proposed that the studies focusing on Asian regions mostly supported the hypothesis, suggesting that more detailed investigations in these regions can enhance our understanding of the hypothesis. We suggest that machine learning algorithms can be a promising synthesis tool especially where studies (a) reformulate a general hypothesis from different perspectives, (b) use different methods or variables, or (c) report insufficient information for conducting metaā€analyses

    Ka-band Ga-As FET noise receiver/device development

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    The development of technology for a 30 GHz low noise receiver utilizing GaAs FET devices exclusively is discussed. This program required single and dual-gate FET devices, low noise FET amplifiers, dual-gate FET mixers, and FET oscillators operating at Ka-band frequencies. A 0.25 micrometer gate FET device, developed with a minimum noise figure of 3.3 dB at 29 GHz and an associated gain of 7.4 dB, was used to fabricate a 3-stage amplifier with a minimum noise figure and associated gain of 4.4 dB and 17 dB, respectively. The 1-dB gain bandwidth of this amplifier extended from below 26.5 GHz to 30.5 GHz. A dual-gate mixer with a 2 dB conversion loss and a minimum noise figure of 10 dB at 29 GHz as well as a dielectric resonator stabilized FET oscillator at 25 GHz for the receiver L0. From these components, a hybrid microwave integrated circuit receiver was constructed which demonstrates a minimum single-side band noise figure of 4.6 dB at 29 GHz with a conversion gain of 17 dB. The output power at the 1-dB gain compression point was -5 dBm

    Particle Topology, Braids, and Braided Belts

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    Recent work suggests that topological features of certain quantum gravity theories can be interpreted as particles, matching the known fermions and bosons of the first generation in the Standard Model. This is achieved by identifying topological structures with elements of the framed Artin braid group on three strands, and demonstrating a correspondence between the invariants used to characterise these braids (a braid is a set of non-intersecting curves, that connect one set of NN points with another set of NN points), and quantities like electric charge, colour charge, and so on. In this paper we show how to manipulate a modified form of framed braids to yield an invariant standard form for sets of isomorphic braids, characterised by a vector of real numbers. This will serve as a basis for more complete discussions of quantum numbers in future work.Comment: 21 pages, 16 figure

    Horizontal gene transfer is a significant driver of gene innovation in dinoflagellates

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    Ā© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Genome Biology and Evolution 5 (2013): 2368-2381, doi:10.1093/gbe/evt179.The dinoflagellates are an evolutionarily and ecologically important group of microbial eukaryotes. Previous work suggests that horizontal gene transfer (HGT) is an important source of gene innovation in these organisms. However, dinoflagellate genomes are notoriously large and complex, making genomic investigation of this phenomenon impractical with currently available sequencing technology. Fortunately, de novo transcriptome sequencing and assembly provides an alternative approach for investigating HGT. We sequenced the transcriptome of the dinoflagellate Alexandrium tamarense Group IV to investigate how HGT has contributed to gene innovation in this group. Our comprehensive A. tamarense Group IV gene set was compared with those of 16 other eukaryotic genomes. Ancestral gene content reconstruction of ortholog groups shows that A. tamarense Group IV has the largest number of gene families gained (314ā€“1,563 depending on inference method) relative to all other organisms in the analysis (0ā€“782). Phylogenomic analysis indicates that genes horizontally acquired from bacteria are a significant proportion of this gene influx, as are genes transferred from other eukaryotes either through HGT or endosymbiosis. The dinoflagellates also display curious cases of gene loss associated with mitochondrial metabolism including the entire Complex I of oxidative phosphorylation. Some of these missing genes have been functionally replaced by bacterial and eukaryotic xenologs. The transcriptome of A. tamarense Group IV lends strong support to a growing body of evidence that dinoflagellate genomes are extraordinarily impacted by HGT.J.H.W. was supported by the NSF IGERT Program in Comparative Genomics at the University of Arizona (grant number DGE-0654435). This work was supported by grants from the National Science Foundation (grant numbers OCE-0723498, EF-0732440) and funding provided by the BIO5 Institute at the University of Arizona to J.D.H

    Group cognitive behavioural therapy for stroke survivors with depression and their carers

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    Background: Depression in stroke survivors is common, leads to poorer outcomes and often not treated. A group cognitive behavioural therapy (CBT) program (Brainstorm) for stroke survivors with depression, and their carers has been running as part of usual care since 2007. Objective: To evaluate the implementation and acceptability of Brainstorm, a closed group intervention consisting of up to 10 sessions of education, activity planning, problem solving and thought challenging. Methods: Participating stroke survivors and their carers complete assessment measures at baseline, post-treatment and 1-month and 6-months follow-up. A mixed models for repeated measures data was conducted with depression and anxiety scores for stroke survivors (Beck Depression Inventory-II; Hospital Anxiety and Depression Scale) and the assessment of depression, anxiety and carer burden for carers. Acceptability was assessed by session attendance and written and open participant feedback upon completion of the program. Results: Forty-eight community dwelling stroke survivors and 34 carers attended Brainstorm, with a median attendance of 88% of sessions. Follow-up assessments were completed by 77% (post-treatment), 46% (1-month) and 38% (6-month) of stroke survivors. Stroke survivorsā€™ depression scores decreased from baseline to post-treatment (p<.001); maintained at 1-month (p<.001) but not at 6-month (p=.056). Anxiety scores decreased between baseline and 1-month (p=.013). Carer burden, depression and anxiety scores at 1-month and 6-month follow-up, for carers, were all reduced when compared with baseline (p<.05). Conclusion: The Brainstorm group intervention for depression in stroke survivors appears to have been effectively implemented and is acceptable to stroke survivors and carers

    Asymptotic quasinormal modes of scalar field in a gravity's rainbow

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    In the context of a gravity's rainbow, the asymptotic quasinormal modes of the scalar perturbation in the quantum modified Schwarzschild black holes are investigated. By using the monodromy method, we calculated and obtained the asymptotic quasinormal frequencies, which are dominated not only by the mass parameter of the spacetime, but also by the energy functions from the modified dispersion relations. However, the real parts of the asymptotic quasinormal modes is still THlnā”3T_H\ln 3, which is consistent with Hod's conjecture. In addition, for the quantum corrected black hole, the area spacing is calculated and the result is independent of the energy functions, in spite of the area itself is energy dependence. And that, by relating the area spectrum to loop quantum gravity, the Barbero-Immirzi parameter is given and it remains the same as from the usual black hole

    A systematic review of non-pharmacological interventions for primary Sjƶgrenā€™s syndrome

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    The objective of this systematic review was to assess the efficacy of non-pharmacological interventions for the management of primary Sjƶgrenā€™s syndrome. We searched the following databases from inception to September 2014; Cochrane Database of Systematic Reviews; Medline; Embase; PsychINFO; Cinahl and clinical trials registers. We included randomised controlled trials of any non-pharmacological interventions. Two review authors independently reviewed titles and abstracts against the inclusion/exclusion criteria and independently assessed trial quality and extracted data. 1463 studies were identified of which 17 full text articles were screened and 5 studies were included in the review with a total of 130 participants randomised. The included studies investigated effectiveness of an oral lubricating device for dry mouth, acupuncture for dry mouth, lacrimal punctum plugs for dry eyes and psychodynamic group therapy for coping with symptoms. Overall the studies were of low quality and at high risk of bias. Although one study showed punctum plugs to improve dry eyes it was too small for the findings to be conclusive. Overall we identified no evidence to support any non-pharmacological interventions to improve PSS. The area needs quality large randomised controlled trials that are reported according to CONSORT guidelines and address important issues to patients

    Motivational Interviewing Post-Stroke: An Analysis of Stroke Survivors' Concerns and Adjustment

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    Our earlier research demonstrated that participation in four sessions of motivational interviewing (MI) early post-stroke has a positive impact on stroke survivors' mood. However, the theoretical underpinnings of MI in supporting adjustment (rather than its traditional use in supporting behavior change) require clarification. This article describes a content analysis of MI transcripts for 10 participants in our previous study, to identify the focus of discussions (patient "concerns") and potential effective components of our MI approach. Patients' post-stroke concerns were shown in 16 categories, including frustration, family impact, and getting well. There was a pattern of change discourse across sessions: "Sustain talk" (reasons for not changing) reduced from Session 1 onward, "change talk" (intent to change) increased then reduced, and "change expressed" (changes achieved) increased from Sessions 1 to 4. MI facilitates healthy adjustment post-stroke in some patients, in turn affecting mood, but clarification of how this effect is achieved requires further exploration

    inVestIgating the pSychologIcal and ecONomic impAct of cataRact surgerY in Vietnam: The VISIONARY observational study protocol

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    <p>Abstract</p> <p>Background</p> <p>Visual impairment caused by cataracts not only affects an individual's quality of life but can also have a profound impact on other important psychological factors and on the economic circumstances of individuals and their households. Cataract surgery is an effective intervention to restore vision and is also associated with other positive consequences including improvements in quality of life, economic and psychological outcomes. While there has been an increase in the number and quality of cataract surgeries performed in Vietnam, the programs currently in place are still unable to meet the existing demand and need for surgery. Data on both the cost-effectiveness of cataract surgery and the economic and psychological impact of untreated cataract in this setting is lacking.</p> <p>Methods/Design</p> <p>This study, investigating the psychological and economic impact of cataract surgery in Vietnam (VISIONARY), will recruit and interview a sample of adults (18 years or over) who are referred for cataract surgery by one of the following sites and their outreach programs: Hue Eye Hospital; Thai Binh Eye Hospital; Binh Dinh Department of Health Eye Hospital and the Vinh Long Department of Health Social Disease Centre. All participants (those who have cataract surgery and those who do not have surgery) will be followed up at six and 12 months.</p> <p>Discussion</p> <p>This study is designed to examine the impact of low vision on household economic circumstances and psychological outcomes as well as to investigate the effectiveness and cost-effectiveness of cataract surgery in Vietnam. It will help to inform international and national non-government organisations working in the country and local policy-makers on priorities for further investment in eye-health services in this setting and their relevance to broader economic development goals.</p
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